You've got a big problem once you overrun Korea, though. The IJN will be on the prowl and it'll take you years and years before you can challenge it in any way. And as far as I understand the warscore will be too small for a peace (no scripted events either), Korea won't be available for release, any amphibious assault would be suicide, and the allies will be perfectly useless for the next few years anyway. Perma-warfare with sporadic assaults by the IJA is your future. And then comes the bigger question. What do you do with the Soviets? Try to stab them in the back when Barbarossa triggers so you can integrate Sianking and Mongolia? That might mean you'll have to wait longer to assault the Home Islands. I'm really curious to see where this is going.